using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Threading;
using System.Xml;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Administration;
using Microsoft.SharePoint.Utilities;
using Microsoft.SharePoint.WebPartPages;
using SPSolutions.SharePoint.Alerts;
using Taloyhtio.CondoUpdate.Common;

namespace CondoUpdate.AddICSFieldToCalendars
{
    public class UpdaterImpl : ICondoUpdater
    {
        private const string ICS_FIELD_NAME = "ICS";
        private const string ALERT_TEMPLATE_BODY_PROPERTY_NAME = "NotificationMessage";

        public event EventHandler<LogEventArgs> OnNotify;
        public void Update(object args)
        {
            string url = args as string;
            if (string.IsNullOrEmpty(url))
            {
                this.warn("Url is empty");
                return;
            }

            try
            {
                this.updateImpl(url);
            }
            catch(Exception x)
            {
                this.error("Error occured during updating of Condo '{0}':\n{1}\n{2}", url, x.Message, x.StackTrace);
            }
        }

        private void updateImpl(string url)
        {
            using (var s = new SPSite(url))
            {
                using (var w = s.OpenWeb())
                {
                    using (var site = new SPSite(s.ID, SPUrlZone.Extranet))
                    {
                        using (var web = site.OpenWeb(w.ID))
                        {
                            if (!web.Exists)
                            {
                                this.warn("Web site '{0}' doesn't exist. It will be ignored", url);
                                return;
                            }

                            Thread.CurrentThread.CurrentCulture =
                                Thread.CurrentThread.CurrentUICulture = new CultureInfo((int) web.Language);

                            this.checkWeb(web);
                        }
                    }
                }
            }
        }

        private void checkWeb(SPWeb web)
        {
            var lists = new List<SPList>();
            foreach (SPList l in web.Lists)
            {
                if (l.BaseTemplate == SPListTemplateType.Events)
                {
                    lists.Add(l);
                }
            }

            lists.ForEach(l =>
                {
                    this.ensureField(l);
                    this.ensureICSLink(l);
                });

            foreach (SPWeb subWeb in web.Webs)
            {
                this.checkWeb(subWeb);
            }
        }

        private void ensureField(SPList l)
        {
            try
            {
                if (l.Fields.Cast<SPField>().Any(f => f.Title == ICS_FIELD_NAME || f.InternalName == ICS_FIELD_NAME))
                {
                    return;
                }
                string fldName = l.Fields.Add(ICS_FIELD_NAME, SPFieldType.Calculated, false);
                var fld = l.Fields[fldName] as SPFieldCalculated;
                fld.Formula = string.Format("=\"{0}/_vti_bin/owssvr.dll?CS=109&Cmd=Display&List={1}&CacheControl=1&ID=\"&{2}&\"&Using=event.ics\"",
                    l.ParentWeb.Url, l.ID, SPUtility.GetLocalizedString("$Resources:ID", "core", l.ParentWeb.Language));
                fld.OutputType = SPFieldType.Text;
                fld.Update();
            }
            catch (Exception x)
            {
                this.error("Error occured when try to add field to list '{0}': {1}\n{2}", l.DefaultViewUrl, x.Message, x.StackTrace);
            }
        }

        private void ensureICSLink(SPList l)
        {
            try
            {
                //var alertTemplate = l.AlertTemplate;
                var alert = getFirstListAlert(l);
                if (alert == null)
                {
                    //log("There are no alerts in the list");
                    return;
                }

                // get alert template from this list
                var alertTemplate = alert.AlertTemplate;
                if (alertTemplate == null)
                {
                    error("Alert's alert template is null (list '{0}')", l.DefaultViewUrl);
                    return;
                }

                if (!isCustom(alertTemplate))
                {
                    error("Alert template '{0}' is not custom (list '{1}')", alertTemplate.DisplayName, l.DefaultViewUrl);
                    return;
                }

                if (alertTemplate.Properties == null || !alertTemplate.Properties.ContainsKey(ALERT_TEMPLATE_BODY_PROPERTY_NAME))
                {
                    error("Alert template '{0}' doesn't have {1} property (list '{2}')", alertTemplate.DisplayName, ALERT_TEMPLATE_BODY_PROPERTY_NAME, l.DefaultViewUrl);
                    return;
                }

                string body = alertTemplate.Properties[ALERT_TEMPLATE_BODY_PROPERTY_NAME] as string;
                if (string.IsNullOrEmpty(body))
                {
                    error("{1} property is empty (list '{1}')", ALERT_TEMPLATE_BODY_PROPERTY_NAME, l.DefaultViewUrl);
                    return;
                }

                if (body.Contains("Using=event.ics"))
                {
                    return;
                }

                int idx = body.IndexOf("&lt;p&gt;Lisätietoja osoitteesta");
                if (idx < 0)
                {
                    return;
                }

                string sub1 = body.Substring(0, idx);
                string sub2 = body.Substring(idx);

                string ics = "&lt;p&gt;&lt;a href=\"{WebAbsolutePublicUrl}/_vti_bin/owssvr.dll?CS=109&amp;Cmd=Display&amp;List={ListId}&amp;CacheControl=1&amp;ID={ID}&amp;Using=event.ics\"&gt;Lataa kalenterikutsu (.ics)&lt;/a&gt;&lt;/p&gt;";

                alertTemplate.Properties[ALERT_TEMPLATE_BODY_PROPERTY_NAME] = sub1 + ics + sub2;
                alertTemplate.Update();
            }
            catch (Exception x)
            {
                this.error("Error occured when try to update alert template for list '{0}': {1}\n{2}", l.DefaultViewUrl, x.Message, x.StackTrace);
            }
        }

        private static SPAlert getFirstListAlert(SPList list)
        {
            var web = list.ParentWeb;
            var alerts = web.Alerts.Cast<SPAlert>();
            return alerts.FirstOrDefault(a => a.ListID == list.ID);
        }

        // This is copy of Alert template's AlertTemplateManager.IsCustom property implementation
        private static bool isCustom(SPAlertTemplate t)
        {
            return (((t.Properties["Custom"] != null) && (t.Properties["Custom"] is string)) && (((string)t.Properties["Custom"]) == SPAlertTemplateUtil.CustomAlertTemplateIdentifier));
        }

        private void info(string msg, params object[] args)
        {
            this.notify(LogLevel.Info, msg, args);
        }

        private void warn(string msg, params object[] args)
        {
            this.notify(LogLevel.Warn, msg, args);
        }

        private void error(string msg, params object[] args)
        {
            this.notify(LogLevel.Error, msg, args);
        }

        private void notify(LogLevel level, string msg, params object[] args)
        {
            this.notify(level, string.Format(msg, args));
        }

        private void notify(LogLevel level, string msg)
        {
            if (this.OnNotify != null)
            {
                this.OnNotify(this, new LogEventArgs { LogLevel = level, Message = msg });
            }
        }
    }
}